Re: 6d mk2 back button focussing

Thanks for very comprehensive and informative answer, I am more than happy now.

what caused me to look at BBF was, my wife does a lot of dog agility, and when I tried to get the dogs in focus over jumps/tunnels at speed, most shots were out of focus.

i played with this and struggled, in the end because I could never get crisp focus of the dog, as often it focused on the jump I changed my approach to give greater depth of field and hopefully catch more in focus dog, this often meant high ISO.

a friend suggested BBF as a method of keeping focus on the moving subject.

Re: 6d mk2 back button focussing

Thanks for very comprehensive and informative answer, I am more than happy now.

what caused me to look at BBF was, my wife does a lot of dog agility, and when I tried to get the dogs in focus over jumps/tunnels at speed, most shots were out of focus.

i played with this and struggled, in the end because I could never get crisp focus of the dog, as often it focused on the jump I changed my approach to give greater depth of field and hopefully catch more in focus dog, this often meant high ISO.

a friend suggested BBF as a method of keeping focus on the moving subject.

lets tryit and experiment.

The problem is two fold. One is focusing a subject whose distance to the camera is changing. One is tracking a subject that is moving across the viewfinder. These are two separate, but inextricably intertwined problems. It is all too easy to conflate the two concepts.

Using BBF will not help you, at least not yet. BBF is for far more experienced users. I used to have a neighbor who trained dobermans for dog shows. He had a neat little obstacle course set up in his backyard. I think I have a pretty good idea of what you might be trying to do.

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I suggest that you select “SCN” on the shooting mode dial. Press the [Q] button, choose the leftmost menu option, which should be the default selection. Use the up/down arrows on the function disc to select “Kids” as the shooting mode.

The camera will be ready to focus and track randomly moving subjects. But, you may need to select active AF points. I suggest enabling multiple AF points to assist you with tracking the moving dogs. Keeping a single AF point on a moving subject takes lots of practice, months and years of it.

Press the [Q} button, and choose the right most menu selection. I think default is “Large Zone AF”. Use the small button [ - - - ] with the dots next to shutter to change the AF point selection option to “Large Zone AF”. There is a picture of the button icon in the menu. You might want to try “Auto Selection AF” mode, too.

What lens are you using to photograph the running and jumping dogs? How far away are you from the dogs?

I use a pair of 7D Mark II, which are excellent with active subjects. Like the 1D/1DX-series cameras, 7D-series use a discrete chip to run the AF system. Dual processors handle images separately. The rest of the Canon cameras use their main processors for everything... incl. both AF and image handling. Lenses I use a lot on my 7DIIs include 70-200mm f/2.8 & f/4 (both IS, USM), 24-70mm f/2.8 USM, 28-135mm IS USM, 300mm f/2.8 IS USM, 300mm f/4 IS USM, 100-400mm IS USM "II", among others.

I typically shoot between 1000 and 4500 images at an event and have less than 1% images that miss focus... and I bet that at least half of those are my fault, not the camera's or lens'. For example, I might shoot too fast, before focus has been acquired.... or I may to keep the AF point on the subject, where I want camera & lens to focus.... or sometimes I just press the wrong button with my thumb!.... or other mistakes. It's pretty rare that I think the camera and lens miss focus.

Part of getting a high success is knowing your subjects and what they are going to do.

I haven't shot dog agility, but do shoot some similar equestrian events. A few examples:

Occasionally I'll use Expansion Points for some types of events, where the subjects change direction less predictably. Gymkhana "Pole Bending" for example, where the horse and rider zig zag through a series of poles.

I use Zone Focus occasionally too, but mostly for birds in flight, against a very distant background or clear sky.

I never use All Points/Auto. It would make for a lot of missed focus shots, I'm afraid.

Besides the camera, lens, settings and familiarity with your subjects, the other thing that's needed is practice, practice, practice! Early in the shooting season I don't get as low percentage of missed focus shots as I do later when I've been doing it a lot.